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Home Energy · Calculator

Home Energy Audit: Estimated Electricity Breakdown

Start from the annual electricity on your bill, then list your appliances. The tool shows an estimated breakdown by category, how much of your real use your list explains, and what each part costs. It is an estimate from your own figures, not a measured split.

Required for the breakdown. Electricity only — gas or oil is not included.

Estimated breakdown

Enter the annual kWh from your bill above to see the breakdown.

Your appliance list currently adds up to 2,685 kWh/year. Without your real total, that is a sum of estimates, not a breakdown of your use.

Your appliances

The starting list is an example — replace the wattages and hours with your own. It is not an average household.

ApplianceCategoryWattsh/daydays/yrkWh/yrCostShare of list
438—16.3%
313—11.6%
525—19.5%
420—15.6%
160—6%
120—4.5%
146—5.4%
175—6.5%
108—4%
105—3.9%
175—6.5%
Total2,685—100%

Your largest lines

  1. 1

    Induction hob

    525 kWh · 20% of the total

  2. 2

    Refrigerator

    438 kWh · 16% of the total

  3. 3

    Dishwasher

    420 kWh · 16% of the total

Next steps

  • Measure your largest or most uncertain line with a plug-in energy meter for a week — it improves the estimate more than any rating label.
  • Thinking about generating your own electricity? The Solar Payback Calculator uses your annual kWh and tariff.
  • Charging an EV at home? Size the charger with Home Charger Sizing, and step through measuring your home in the DIY home energy audit guide.

How the math works

Annual kWh = watts × hours/day × days/year ÷ 1000

Annual cost = kWh × your tariff

Annual CO₂e = kWh × chosen electricity factor (optional)

Not yet listed = bill kWh − sum of your lines (if positive)

Share = category kWh ÷ bill kWh

Example: a 2,200 W kettle used 0.15 h a day all year uses 2,200 × 0.15 × 365 ÷ 1000 = 120.5 kWh. Appliances that cycle (fridges, freezers) need effective running hours, not 24. The result is only as good as the wattages and hours entered.

Example: with a 3,500 kWh bill and a list adding up to 2,800 kWh, the list explains 80% and 700 kWh is shown as not yet listed. At 0.30/kWh the parts cost 840 + 210 = 1,050, the same as 3,500 × 0.30. All assumptions are summarised on the methodology page.

Frequently asked questions

How is annual energy use calculated per appliance?
Annual kWh = watts × hours per day × days per year ÷ 1000. Cost = kWh × your tariff. For devices that cycle on and off (fridges, freezers, air conditioners) enter the effective running hours, or better, measure them with a plug-in energy meter.
Why do I need my annual kWh from a bill?
Without a measured total, an appliance list only adds up guesses. With the annual kWh from your bill or meter as the baseline, the calculator shows how much of your real use your list explains and how much is not yet listed. The categories then always add up to your actual total.
What does "Not yet listed" mean?
It is the part of your bill baseline that your appliance lines do not account for: devices you have not added, underestimated hours, or heating and hot water on the same meter. It is not assigned to any category, because no generic household split is assumed.
What do the pre-filled appliances represent?
They are an example list to show how the audit works — not an average household. Replace every wattage and duration with your own, delete lines you do not have and add the ones you do.
Why is my estimate different from my bill?
Nameplate wattage is often higher than average draw, durations are hard to estimate, and lines you have not added (for example electric heating) are missing. Standing charges are not per-kWh. Compare the audit total with the kWh on your bill rather than the money total.
How do I add electric heating or an EV?
Add a line with its average power and running hours, or enter its annual kWh as an equivalent (for example, 3,000 kWh = 1,000 W × 8.22 h × 365 days). For a heat pump, use the heat pump savings calculator to estimate electricity from heat demand and SCOP first.
Is this an energy-efficiency assessment?
No. It estimates electricity use and cost from the figures you enter. It does not rate your home or recommend building works; for that you need an accredited assessor.
How are emissions calculated?
Optional: total kWh × the electricity factor you choose (UK 2025 or US eGRID2023 averages, or your own). It is an average-grid estimate and does not change with a green tariff.

Keep exploring

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Standby Power Audit

Focus on always-on devices.

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Heat Pump Savings

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Solar Payback

Savings and payback from your own generation estimate.

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EV Charging Cost

Work out your EV's annual kWh to add here.

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DIY home energy audit guide

Set a baseline, measure loads and prioritise what to change.

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Home Charger Sizing

If EV charging is a large line, size the charger to your driving.

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Methodology

Formulas and assumptions behind every tool.

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Smart-home savings guide

Ways to reduce and shift household electricity use.